For the 16th year, Special Olympics Iowa has persuaded people to jump into Big Creek Lake at Polk City as part of its Polar Plunge fundraiser.

The main event is today, but at noon Friday, hardy souls whom organizers called “Super Plunge” jumpers got wet in the first of 24 hourly jumps leading up to this morning’s finale. The temperature was about 46 degrees at noon, with that figure expected to drop below 40 overnight.

Special Olympics Iowa said it hoped to raise $40,000 in donations from the event.